Contents
dpotrs - solve a system of linear equations A*X = B with a
symmetric positive definite matrix A using the Cholesky fac-
torization A = U**T*U or A = L*L**T computed by DPOTRF
SUBROUTINE DPOTRS(UPLO, N, NRHS, A, LDA, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER N, NRHS, LDA, LDB, INFO
DOUBLE PRECISION A(LDA,*), B(LDB,*)
SUBROUTINE DPOTRS_64(UPLO, N, NRHS, A, LDA, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER*8 N, NRHS, LDA, LDB, INFO
DOUBLE PRECISION A(LDA,*), B(LDB,*)
F95 INTERFACE
SUBROUTINE POTRS(UPLO, [N], [NRHS], A, [LDA], B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER :: N, NRHS, LDA, LDB, INFO
REAL(8), DIMENSION(:,:) :: A, B
SUBROUTINE POTRS_64(UPLO, [N], [NRHS], A, [LDA], B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, NRHS, LDA, LDB, INFO
REAL(8), DIMENSION(:,:) :: A, B
C INTERFACE
#include <sunperf.h>
void dpotrs(char uplo, int n, int nrhs, double *a, int lda,
double *b, int ldb, int *info);
void dpotrs_64(char uplo, long n, long nrhs, double *a, long
lda, double *b, long ldb, long *info);
dpotrs solves a system of linear equations A*X = B with a
symmetric positive definite matrix A using the Cholesky fac-
torization A = U**T*U or A = L*L**T computed by DPOTRF.
UPLO (input)
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
N (input) The order of the matrix A. N >= 0.
NRHS (input)
The number of right hand sides, i.e., the number
of columns of the matrix B. NRHS >= 0.
A (input) The triangular factor U or L from the Cholesky
factorization A = U**T*U or A = L*L**T, as com-
puted by DPOTRF.
LDA (input)
The leading dimension of the array A. LDA >=
max(1,N).
B (input/output)
On entry, the right hand side matrix B. On exit,
the solution matrix X.
LDB (input)
The leading dimension of the array B. LDB >=
max(1,N).
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an ille-
gal value